Study of medicinal plants and their chemical constituents
B.
The branch of chemistry that deals with the origin, transport, reactions, effects and fates of chemical species in the environment (air, water, soil, living organisms)
C.
Study of chemical reactions occurring inside living organisms
D.
Study of natural resources and their commercial exploitation
B. The branch of chemistry that deals with the origin, transport, reactions, effects and fates of chemical species in the environment (air, water, soil, living organisms)
2.
An ENVIRONMENTAL POLLUTANT is defined as:
A.
Only synthetic chemicals released by human industrial activity
B.
Any substance present in the environment in an amount that is harmful to living beings or causes imbalance in the ecosystem, whether natural or man-made
C.
Any chemical compound found in the atmosphere
D.
Only radioactive substances released from nuclear plants
B. Any substance present in the environment in an amount that is harmful to living beings or causes imbalance in the ecosystem, whether natural or man-made
3.
The ATMOSPHERE is divided into layers. Which layer extends from the Earth's surface to approximately 10 km altitude?
A.
Mesosphere — extends from 50 to 85 km altitude
B.
Stratosphere — extends from 10 to 50 km altitude
C.
Troposphere — the lowest layer where all weather phenomena and most air pollution occur; temperature decreases with altitude at ~6.5°C/km (lapse rate)
C. Troposphere — the lowest layer where all weather phenomena and most air pollution occur; temperature decreases with altitude at ~6.5°C/km (lapse rate)
4.
The STRATOSPHERE extends from approximately 10 km to 50 km altitude. Its most important chemical feature is:
A.
The presence of photochemical smog that damages respiratory health
B.
The OZONE LAYER (at ~20–30 km altitude) which absorbs harmful UV radiation (especially UV-B and UV-C) from the Sun, protecting life on Earth
C.
The high concentration of nitrogen oxides that cause acid rain
D.
The presence of high concentrations of carbon dioxide that causes global warming
B. The OZONE LAYER (at ~20–30 km altitude) which absorbs harmful UV radiation (especially UV-B and UV-C) from the Sun, protecting life on Earth
5.
Dinitrogen (Nâ‚‚) and dioxygen (Oâ‚‚) are major atmospheric constituents but do NOT react with each other under normal conditions because:
A.
They repel each other because they are both diatomic molecules
B.
Both are non-polar molecules and non-polar molecules never react with each other
C.
Their ionisation energies prevent them from combining under normal conditions
D.
Both N₂ and O₂ have very high bond energies (N≡N = 945 kJ/mol; O=O = 499 kJ/mol) — the activation energy for their reaction is extremely high, so they don't react at normal atmospheric temperatures
D. Both N₂ and O₂ have very high bond energies (N≡N = 945 kJ/mol; O=O = 499 kJ/mol) — the activation energy for their reaction is extremely high, so they don't react at normal atmospheric temperatures
6.
The PRIMARY gaseous air pollutants in the troposphere include:
A.
Chlorine gas and fluorine gas emitted by chemical industries only
B.
Oxides of sulphur (SO₂, SO₃), oxides of nitrogen (NO, NO₂), oxides of carbon (CO, CO₂), hydrocarbons and hydrogen sulphide (H₂S)
C.
Only particulate matter — dust, smoke and pollen
D.
Ozone, PAN and formaldehyde only (these are secondary pollutants)
